BN(O) citizens are subject to immigration controls and do not have a right of abode in the UK.
The new Hong Kong BN(O) Visa will allow BN(O) citizens to reside and work or study in the UK, with a pathway to settlement (also known as permanent residence or indefinite leave to remain)
1.Generally, individuals must be resident and ‘settled’ in the UK on the first day of the first academic year of their course to be eligible for home student status.
2.they must also have been ‘ordinarily resident’ in the UK for the three years before that date.A person is ordinarily resident if they normally and lawfully live in an area from choice.
Note. A settled person is someone ordinarily resident in the UK without any immigration restriction on the length of their stay.
Tuition fees for Home students 2022: £9,250 for the year
International tuition fees for 2022: £23,340
source:
https://www.undergraduate.study.cam.ac.uk/international-students/international-fees-and-costs